News - B Vitamins may slow the march towards Alzheimer’s Disease

Daily supplementation of B vitamins slow the rate of brain shrinkage in elderly people suffering from mild mental decline, and may even halt their progression towards Alzheimer’s disease.

Our brains naturally shrink as we age. But the actual rate of brain shrinkage is related to the development of dementia.

Dementia is a disease found in increasing numbers of people. It presents itself in many different forms and ranges from mild cognitive impairment (MCI), where people experience mild memory decline, to the more debilitating forms such as Alzheimer’s disease.

Approximately 16% of elderly people over the age of 70 have MCI, and typically display a greater rate of brain shrinkage than their cognitively healthy counterparts. About half of those with MCI ultimately go on to develop Alzheimer’s within five years, and the rate of brain shrinkage is known to be even higher in these individuals. MCI is therefore a very strong risk factor for Alzheimer’s disease.

Scientists at the University of Oxford recently conducted a two-year randomised, double-blind controlled trial to determine whether a vitamin pill containing high doses of folic acid, vitamin B6 and Vitamin B12 could reduce the rate of brain shrinkage in elderly individuals diagnosed with MCI.

Homocysteine is an amino acid found in the blood, and high blood levels of homocysteine are linked to an increased risk of brain shrinkage, cognitive impairment and dementia. Folic Acid, B6 and B12 are three vitamins known to regulate the amount of homocysteine. They play key roles in rendering homocysteine harmless by converting it to the amino acids methionine and cysteine. Without enough of these B vitamins, this conversion becomes inefficient resulting in abnormally elevated levels of homocysteine.

The Oxford researchers scanned the brains of 168 volunteers aged 70 or over to determine the rate of brain shrinkage per year. They divided the volunteers into two groups, one group received daily doses of folic acid, B6 and B12, and the other group received inactive ‘dummy’ placebo pills.

The results published in the journal Public Library of Science (PLoS) ONE, showed that the group given homocysteine-lowering B vitamins experienced on average 30% less brain shrinkage per year than those given the placebo.

The effect of the B vitamins was most pronounced in those whose homocysteine levels were higher at the start of the trial, with their brains shrinking at half the rate of those taking the placebo pills. The researchers also found that those whose brains shrank the slowest had higher cognitive test scores at the end of the trial compared to those whose brains were shrinking fast.

Commenting on the results, David Smith, Emeritus Professor of Pharmacology at the University of Oxford and first author of the study said: “It is our hope this simple and safe treatment will delay the development of Alzheimer’s disease in many people.” While Professor Smith recommends that anybody thinking of taking these B vitamins should consult their doctor first, he observes: “if I had MCI I would take it.”

A spokesman for the Alzheimer’s Society said: “This is an interesting study which could change the lives of thousands of people at risk of dementia.”

Dr Smith is currently planning another trial at Oxford to determine whether this treatment with B vitamins can slow or reduce the number of people with MCI who go on to develop Alzheimer’s.